The present invention relates to a file sharing system and a file sharing method, and, for instance, can be suitably applied to a file sharing system and a file sharing method that protects the privacy of users using files stored in an online file storage, which is accessed by an unspecified number of information processing units, upon sharing such files with third parties.
A user is able to store files in one's PC (Personal Computer) in an online file storage or file server as represented by “Amazon (registered trademark) S3 (Simple Storage Service)” via the Internet. With these network-connected storage apparatuses, NFS (Network File System), HTTP (Hyper Text Transfer Protocol), or the like is used upon storing files in the online file storage.
With NFS and HTTP, the storage apparatus-side possesses the file system function, and the file system centrally controls the account information database, the file path name, and the physical layout of files in the disk drive.
The online file storage authenticates a client by verifying the account name and password designated by the client with the account information database. The online file storage manages the access authority information per file, and prevents unauthorized access by only permitting the account possessing access authority to access the relevant file.
A file is provided with a path name for uniquely identifying the files in the online file storage. The path name is configured from a hierarchy of a directory storing the file and the file name. Although an arbitrary character string can be used as the hierarchy of directory and the file name, under normal conditions a unique name or numbers are used so that the file creator will be able to understand the contents of the file. The path name of the file is being managed by the online file storage storing such file (for instance, refer to http://aws.amazon (registered trademark).com/s3).
There is also technology known as “CleverSafe (registered trademark)” or “pNFS” that enables the use of a plurality of online file storages connected to a network as a single virtual storage apparatus. This technology is configured from an online file storage storing files, a client that accesses the files, and a metadata server for managing the location of the files.
The metadata server authenticates a client by verifying the account name and password designated by the client with the account information database. The online file storage also authenticates a client by verifying the account name and password designated by the client with the account information database. In the case of “CleverSafe,” a single account information database is used among the metadata server, the online file storage, and the client. The user or application only needs to log on one time to the client, and does not need to remember the account information for each metadata server or plurality of online file storages. Upon creating a file, the client designates the path name of the file to be created and issues a file creation request to the metadata server. Meanwhile, the metadata server determines the position; that is, in which online file storage the file is to be stored, and returns such position information to the client. The client stores the file in the designated online file storage. The path name of the file is managed by the metadata server. A plurality of metadata servers may exist, and may respectively possess an independent name space.